In International Patent Application No. PCT/US 84/00226 (International Publication No. WO 85/03750) a torsion spring cartridge assembly is disclosed which may be used for supporting wheels on trailers or other vehicles, and has significant advantages over its prior art. A corresponding U.S. application of the same title exists: U.S. application Ser. No. 781,149, filed Aug. 14, 1985.
As one disadvantage of the structure disclosed in the International Application, it is relatively expensive to manufacture. Additionally, if subjected to excessive loads or bumps, the torsion spring cartridge assembly of the International Application can rotate beyond its mechanical limits, causing breakage of the torsion rod system used therein.
There is need for a suspension system for vehicles or any other desired use in which the system is protected against damage by overload. Also, there is a need to increase the manufacturing efficiency and to reduce the expense of the desired suspension system so that the system is not only less likely to break on overload, but is of reduced cost.
Additionally, large objects may have the suspension system of this invention installed under them for the temporary addition of wheels. Then, they may be rolled to a desired location, and the suspension systems may be removed and used elsewhere.
Additionally, the amount of torsion can be adjusted by varying the number of torsion bars used in the system, so that the same torsion bar suspension unit may be easily modified by simply adding or subtracting torsion bars as may be desired. Furthermore, upon axle failure following abuse of the system, torsion bar systems in accordance with this invention have much less tendency to cause loss of control.